<html>
<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<meta http-equiv="X-UA-Compatible" content="ie=edge">
	<title>求圆的周长和面积</title>
</head>
<body>
	<p>园的半径 ：<input type="text" id="ban" placeholder="半径"/></p>
	<p>园的周长 ：<input type="text" id="zhou" placeholder="周长"/></p>
	<p>园的面积 ：<input type="text" id="mian" placeholder="面积"/></p>
		<script src="yuan.js" type="text/javascript" charset="utf-8"></script>
</body>
</html>